{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-97417","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-24T14:53:16.867Z","datePublished":"2026-09-24T16:03:27.069Z","dateUpdated":"2026-10-03T10:58:08.961Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-10-03T10:58:08.961Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack()\n\nThe timestamp-only fast path dereferences the option stream as\n*(__be32 *)ptr, which assumes 4-byte alignment that the TCP option\nstream does not guarantee. Use get_unaligned_be32() instead, which\nreads the value safely and already returns host byte order, so the\nhtonl() on the comparison constant can be dropped.\n\nThis matches the existing get_unaligned_be32() use later in the same\nfunction."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - ipv4_conntrack_in() on NF_INET_PRE_ROUTING calls nf_conntrack_in()→nf_conntrack_tcp_packet()→tcp_in_window()→tcp_sack(); the *(__be32 *)ptr load reads the first four option bytes of a received TCP segment (doff=8, 12-byte NOP-NOP-TIMESTAMP block) that the remote peer put on the wire.\nAC:L - Default tcp_loose=1 makes tcp_new() set IP_CT_TCP_FLAG_SACK_PERM on both directions for a non-SYN ACK, so one attacker TCP ACK with doff=8 (length==TCPOLEN_TSTAMP_ALIGNED) reaches tcp_sack()'s timestamp fast path; on strict-alignment NAT/PPPoE paths where those options are 2-mod-4, *(__be32 *)ptr faults with no race.\nPR:N - ipv4_conntrack_in()/ipv6_conntrack_in() run in NF_INET_PRE_ROUTING; tcp_error() only checks header length, flags, and checksum before nf_conntrack_tcp_packet() reaches tcp_sack(), with no socket, credentials, or TCP-handshake authentication.\nUI:N - The PRE_ROUTING conntrack hook invokes tcp_sack() from softirq on the attacker's own TCP segment; no victim must mount media, open a file, or take any other interactive action.\nS:U - An alignment fault in tcp_sack() oopses the same host kernel that is conntracking the TCP flow; it does not cross a VM, guest-to-host, IOMMU, or other security authority.\nC:N - The timestamp fast path loads four in-bounds bytes of the packet's own TCP option stream after skb_header_pointer(..., length==12, ...); it is not an OOB or UAF read, and a strict-alignment fault discloses nothing beyond those attacker-supplied bytes.\nI:N - tcp_sack()'s defect is a read-only *(__be32 *)ptr of the option bytes; it does not write conntrack state or adjacent objects, and the fix only replaces that load with get_unaligned_be32().\nA:H - On SPARC, MIPS, and pre-v6 ARM (typical OpenWrt/CPE NAT boxes), the misaligned __be32 load in tcp_sack() raises a kernel alignment exception/oops/panic in netfilter softirq, fully denying host availability and repeatable by resending the segment."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nf_conntrack_proto_tcp.c"],"versions":[{"version":"bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9","lessThan":"740ad3d17a281f7764dda4dbeb37cea52e2e31ae","status":"affected","versionType":"git"},{"version":"bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9","lessThan":"a0523267de2523522b0f70972dd1ffa22ec6176c","status":"affected","versionType":"git"},{"version":"bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9","lessThan":"55bcc3376cd7b18954cc9814da697504fdaf12bf","status":"affected","versionType":"git"},{"version":"bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9","lessThan":"0d5ad732e4fdc569eb85861115e8f7b4c2c67852","status":"affected","versionType":"git"},{"version":"bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9","lessThan":"7ecfa46a536578a7ed335ddf31a854127268c27c","status":"affected","versionType":"git"},{"version":"bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9","lessThan":"4abc1af7ac209c066f4e5dd75cdd56876e5829a9","status":"affected","versionType":"git"},{"version":"bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9","lessThan":"d3bf9eae486490832bd08fd62ab0ac601f346bd4","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nf_conntrack_proto_tcp.c"],"versions":[{"version":"3.1","status":"affected"},{"version":"0","lessThan":"3.1","status":"unaffected","versionType":"semver"},{"version":"5.10.271","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.222","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.189","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.111","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.53","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"5.10.271"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"5.15.222"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.1.189"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.12.111"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.18.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/740ad3d17a281f7764dda4dbeb37cea52e2e31ae"},{"url":"https://git.kernel.org/stable/c/a0523267de2523522b0f70972dd1ffa22ec6176c"},{"url":"https://git.kernel.org/stable/c/55bcc3376cd7b18954cc9814da697504fdaf12bf"},{"url":"https://git.kernel.org/stable/c/0d5ad732e4fdc569eb85861115e8f7b4c2c67852"},{"url":"https://git.kernel.org/stable/c/7ecfa46a536578a7ed335ddf31a854127268c27c"},{"url":"https://git.kernel.org/stable/c/4abc1af7ac209c066f4e5dd75cdd56876e5829a9"},{"url":"https://git.kernel.org/stable/c/d3bf9eae486490832bd08fd62ab0ac601f346bd4"}],"title":"netfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack()","x_generator":{"engine":"bippy-1.2.0"}}}}